The profile's author David Pierce got to visit the building on Microsoft's campus where it tests upcoming products.

And he noticed something out of place. Emphasis ours:

But as soon as we start talking about it, he gets distracted by a CNC machine that's milling a Surface Book's bottom bucket. Panay just watches it for a moment, carving over and over to form the antenna gap. A few machines away, another machine works on a prototype of a new phone.

Although there have been reports and rumors that Microsoft wants to make its own phone, this is the first time we've seen real evidence that the company is working on smartphone prototypes.

Microsoft does make phones under the Lumia brand, but those come from its acquisition of Nokia, which closed last year. Since then, Microsoft has fired most of the former Nokia employees.

There's a chance it'll extend the Surface brand to phones too, and the prototype mentioned in Wired's profile could be the long-awaited Surface Phone.